A3 2.0 TDI Rough Idle When Hot (Video)

[Luey]

Hey everyone,

Got another problem with my nightmare Audi. I have been to two experts and they don't have a clue what the problem is.

After a drive, once the car is warm, the car seems to idle rough. The exhaust note drops and sounds throaty. I haven't noticed any smoke but that could be due to the DPF and I can't really feel a drop in power. After about a minute sitting the car very suddenly drops back to it's original exhaust note. 

Additionally a very faint clicking can be heard down the exhaust. However cannot hear anything out of the ordinary towards the engine. 

I also have a couple OBDEleven faults

Cylinder 1 Injector short to B+ (intermittent) and IMRC Intake Manifold Runner Control fault also intermittent. Any ideas what short to B+ means and cause also IMRC I have no ideas about as I deleted the swirl flaps a year ago without issues. Throttle body?

I suspect it could be a faulty EGR, coolant sensor, maybe injector? 

Can also have issues on rare occasions starting, super lumpy idle. I think thats a misfire on injector one. Which is showing as a fault on the first injector. However drives fine so not sure this is causing the issues with the sound when hot. 

Any ideas would be appreciated

[cliffcoggin]

I have no idea what the codes mean, but there is little doubt that an intermittent injector fault would give the rough idling symptoms you describe. Who are these experts you consulted? Did they not suggest any solution?

[Luey]

Actually they couldn't find the fault and refused to charge me. Which was nice for my wallet.

They have offered to take another look when it goes in for a routine cambelt and waterpump. However I am reluctant to spend the £400 on that without having this fixed first. 

On top of all this I need the prop shaft centre support bearing replaced. Which Audi no longer do... so have to buy the parts from Australia or aftermarket from US then another £400 to fit. 

[Southampton Graham]

Hi Luey

For your prop shaft centre support have you tried Seat or Skoda as they generally use the same parts?

Part number 1KO 521 349 I think

[Luey]

1 hour ago, Southampton Graham said:

Hi Luey

For your prop shaft centre support have you tried Seat or Skoda as they generally use the same parts?

Part number 1KO 521 349 I think

Actually that's really helpful. I had a quick look but they seem more expensive than what I have found. My concern however is the cost of dropping the exhaust, then the propshaft... splitting it... keeping it balanced... fitting the new bearing then putting it all back. It's going to cost a pretty penny. I reckon within a year I will need a new clutch and flywheel. This car is seriously expensive.